Conventionally, there is known an internal combustion engine that promotes combustion of a fuel air mixture in a combustion chamber utilizing an electromagnetic wave.
Japanese Unexamined Patent Application, Publication No. 2007-113570 discloses an internal combustion engine that includes an ignition device that causes a plasma discharge by emitting a microwave to a combustion chamber before or after ignition of a fuel air mixture. The ignition device generates local plasma using a discharge by an ignition plug so that the plasma is generated in a high pressure field, and grows the plasma using the microwave. The local plasma is generated at a discharge gap between a tip end part of an anode terminal and a ground terminal part.